You can use C++ libraries from Rust. That's a very normal thing to do. People start new projects in C++ either because they themselves don't want to learn a new thing or because they don't want their employees spending time learning a new thing.
I doubt it. You can use C libraries from Rust, and emit C libraries in C++.
> because they themselves don't want to learn a new thing or because they don't want their employees spending time learning a new thing.
Whining about others not wanting to learn when you could have learned how Rust FFI works is, really, hilarious :-)